1. Field of the Invention
The present invention relates to an ink, an ink cartridge and an ink jet recording method.
2. Description of the Related Art
An ink jet recording method is such a recording method that minute droplets of an ink are applied to a recording medium such as plain paper to form an image, and is rapidly spread owing to low price of an apparatus itself and improvement of recording speed. In general, a recorded article obtained by the ink jet recording method is low in fastness properties of an image thereof compared with a silver salt photograph. In particular, when the recorded article is exposed to light, moisture, heat or environmental gas present in air, such as an ozone gas for a long period of time, there is a problem that a coloring material of the recorded article is deteriorated to easily cause change in color tone or fading of the image.
Since the change in color tone or fading of the image is caused especially by a cyan ink low in ozone resistance among respective inks of cyan, yellow and magenta as a main factor, there are a great number of proposals for improving the ozone resistance of the cyan ink. For example, there is a proposal on an ink in which two kinds of coloring materials (dyes) having a phthalocyanine skeleton are caused to be contained, thereby improving the ozone resistance of an image (see Japanese Patent Application Laid-Open No. 2009-057540).
As another problem in the cyan ink using the phthalocyanine compound, metallic luster, what is called a bronzing phenomenon, caused by high aggregation property of the phthalocyanine compound is mentioned. When the bronzing phenomenon is caused, the optical reflecting properties of the image recorded are changed, and so the hue thereof looks markedly different to cause lowering of image quality. The bronzing phenomenon is considered to be caused by aggregation of the coloring material on the surface of a recording medium or in the neighborhood thereof due to high aggregation property of the coloring material and due to lowering of permeability of an ink into the recording medium when the ink is applied to the recording medium.